In a correlational study,
2 variables are measured and there is only 1 group of participants.
A recent study reports that students who just finished playing a prosocial video game were more likely to help others than students who had played a neutral or antisocial game. For this study, what is the independent variable?
The kind of game given to the students
What additional information is obtained by measuring two individuals on an ordinal scale compared to a nominal scale?
The direction of the difference
What additional information is obtained by measuring two individuals on an interval scale compared to a ordinal scale?
The size of the difference
What kind of variable requires the use of real limits?
Continuous
One sample has n = 4 scores and M = 10. A second sample has n = 8 scores and M = 4. If the two samples are combined, what is the mean for the combined sample?
72/12 = 6
My electric bills for June, July, and August last summer were $75, $75, and $150, respectively. What was the mean amount for the three bills?
$100
A sample has a mean of M = 86. If one new person is added to the sample, what effect will it have on the sample mean?
Cannot be determined from the information given
What is the most likely shape for a distribution with a mean of 40 and a mode of 45?
Negatively skewed
One sample with n = 4 scores has a mean of M = 12, and a second sample with n = 6 scores has a mean of M = 8. If the two samples are combined, what is the mean for the combined set of scores?
9.6
How many individual scores are in the following distribution?
n = 10
What kind of frequency distribution graph shows the frequencies as bars that are separated by spaces?
A bar graph
What is the shape of the distribution for the following set of data?
Symmetrical
If a distribution of scores is shown in a bar graph, you know that the scores were measured on a(n) _________ scale of measurement.
nominal or ordinal
A sample of n = 15 scores ranges from a high of X = 11 to a low of X = 3. If these scores are placed in a frequency distribution table, how many X values will be listed in the first column?
9
A sample of n = 9 scores has a variance of s2 = 18. If the scores were a population, what value would be obtained for the population variance.
s2 = 16
Which of the following actions will have no effect on the value of the standard deviation?
Subtract 5 points from every score in the distribution
A researcher takes a sample from a population and computes a statistic for the sample. Which of the following statements is correct?
None of the other statements is correct.
What is the variance for the following population of scores? Scores: 5, 2, 5, 4
1.5
A population of N = 100 scores has m = 30 and s = 4. What is the population variance?
16
For a population with a standard deviation of s = 10, what is the z-score corresponding to a score that is 5 points below the mean?
z = -0.50
Last week Tim got a score of X = 54 on a math exam with m = 60 and s = 8. He also got X = 49 on an English exam with m = 55 and s = 3, and he got X = 31 on a psychology exam with m = 37 and s = 4. For which class should Tim expect the best grade?
Math
A distribution with m = 35 and s = 8 is being standardized so that the new mean and standard deviation will be m = 50 and s = 10. In the new, standardized distribution, your score is X = 45. What was your score in the original distribution?
X = 31
A sample of n = 20 scores is transformed into z-scores. What is the mean for the set of 20 z-scores?
0
For a sample with M = 50 and s = 12, what is the X value corresponding to z = -0.25?
47
A normal distribution has a mean of m = 40 with s = 10. If a vertical line is drawn through the distribution at X = 35, what proportion of the scores are on the left side of the line?
0.3085
A normal distribution has a mean of m = 80 with s = 20. What score separates the lowest 30% of the distribution from the rest of the scores?
X = 69.6
A normal distribution has a mean of m = 70 with s = 12. If one score is randomly selected from this distribution, what is the probability that the score will be greater than X = 55?
0.8944
Which of the following is a requirement for a random sample?
All of the other 3 choices are correct.
A vertical line drawn through a normal distribution at z = -1.00 separates the distribution into two sections, the body and the tail. What proportion of the distribution is in the body?
0.8413
A sample of n = 4 scores is selected from a population with m = 50 and s = 12. If the sample mean is M = 56, what is the z-score for this sample mean?
1.00
A sample of n = 16 scores is selected from a population with m = 80 with s = 20. On average, how much error would be expected between the sample mean and the population mean?
5 points
A sample of n = 4 scores is obtained from a population with m = 70 and s = 8. If the sample mean corresponds to a z-score of 2.00, what is the value of the sample mean?
M = 78
A random sample of n = 60 scores is selected from a population. Which of the following distributions definitely will be normal?
The distribution of sample means will form a normal distribution.
Under what circumstances will the distribution of sample means be normal?
If the population is normal or if the sample size is greater than 30